Version:            (using KDE KDE 3.5.7)
Installed from:    Ubuntu Packages

Cameras that can save raw files often allow to store both formats (jpg and raw) for an image at the same time. That means you'll have two files of the same image.
I think it would be helpful to add a little support for that situation.

Currently digikam just displays all files in an album which means the jpg and the raw files are displayed. This is not what I normally wants, espacially raw file display is slow in comparison to jpg.

I suggest to hide the raw file when there's an jpg. This could look like this:

(I assume that the raw file has the same base file name as the jpg so the raw file can be detected as an duplicate.)

By default the duplicate raw file will be hidden but the thumbnail could indicate the existance of different formats with additional info like icons. These icons should be in grey for example not to be anoying for the user. Maybe just place '(RAW)' after the file name: IMG_1234.JPG (RAW)

I call this 'grouped mode'.

The view behaviour could be switched:
- show raw files grouped (default)
- show raw files ungrouped (like digikam behaves now)
- show raw files only

The problem is how actions (edit, delete, ...) should work in grouped mode. while file operationes (move, delete, ...) and meta data actions like tagging should work on both files, viewing and editing should work with the jpg by default. The context menu could have additional entries: 
- Edit RAW ... (configurable external tool)
- Open RAW with ...

I can imagine that there might be more side effects implementing this feature. For example when the external RAW converter overwrite the JPG the meta data might need to be rewritten to the file.